“The adventure is over!” said Anne. “How queer — I didn’t think it was one while it was happening — but now I see it was!”

“Another to add to our long list of adventures,” said Julian. “Cheer up, Martin — don’t look so blue. Whatever happens, we’ll see you don’t come out badly over this. You helped us, and you threw in your lot with us. We’ll see that you don’t suffer — won’t we, Uncle Quentin? We’d never have got through those falls of rock if we hadn’t had Martin and his spades!”

“Well — thanks,” said Martin. “If you can get me away from my guardian — and never let me see him again — I’d be happy!”

“It’s quite likely that Mr Curton will be put somewhere safe where he won’t be able to see his friends for quite a long time,” said Uncle Quentin dryly. “So I don’t think you need worry.”

As soon as the boats reached shore, Julian, Dick, Timmy and Uncle Quentin went off to the quarry to see if Mr Curton was still there — and to wait for the other two men to come out of the tunnel!

Mr Curton was there all right, still groaning and calling for help. Uncle Quentin spoke to him sternly.

“We know your part in this matter, Curton. You will be dealt with by the police. They will be along in a short while.”

Timmy sniffed round Mr Curton, and then walked away, nose in air, as if to say “What a nasty bit of work!” The others arranged themselves at the mouth of the hole and waited.

But nobody came. An hour went by — two hours. Still nobody. “I’m glad Martin and Anne didn’t come,” said Uncle Quentin. “I do wish we’d brought sandwiches.”

At that moment the police arrived, scrambling down the steep sides of the quarry. The police doctor was with them and he saw to Mr Curton’s leg. Then, with the help of the others, he got the man to the top with great difficulty.

“Julian, go back and get sandwiches,” said Uncle Quentin at last. “It looks as if we’ve got a long wait!”

Julian went back, and was soon down the quarry with neat packets of ham sandwiches and a thermos of hot coffee. The two policemen who were still left offered to stay and watch, if Uncle Quentin wanted to go home.

“Dear me, no!” he said. “I want to see the faces of these two fellows when they come out. It’s going to be one of the nicest moments of my life! The island is not blown up. My secret is safe. My book is safe. My work is finished. And I just want to tell these things to my two dear friends!”

“You know, Father, I believe they’ve lost their way underground,” said George. “Julian said there were many different passages. Timmy took the boys through the right ones, of course — but they would have been quite lost if they hadn’t had him with them!”